It seems that people misunderstood this topic a bit.
First of all, when I say an episode triggers me, I don't mean it sends me into a rage or anything of te sort. I mean I find it off putting to an extreme degree.
Secondly, I'm not attempting to degrade, take advantage of, or abuse anything. I thought "trigger" had many meanings, not just the actual medical term.
I'm sorry.

Let's have a nice little thread to talk about the episodes that we find truly off-putting. These aren't episodes we dislike; these are episodes we hate, and we want the world to know, dangit.
For me, the first episode that always comes to mind is "The Best Night Ever." This episode and its "moral" annoys me on so many levels. What even was it? Never look forward to anything? Don't go to parties? Always stay with your established friends and don't branch out? On a logical level, I understand the idea was "don't overhype anything", but it was executed so questionably. Seeing the Mane6 have their hopes and dreams dashed isn't particularly enjoyable (even if there are funny moments), and them making total jerks of themselves by ruining the gala for everyone isn't fun either. Oh, but don't worry; according to Celestia, that doesn't matter because the gala is always "boring!" Let's all laugh about it! Seriously... what? It's especially jarring since this was a season finale that was (somewhat) built up throughout the season.
Enough about me though. I want to know which episodes upset all of you.

Same. It's partly because my family doesn't celebrate Christmas, and partly because I think most holidays are a bit silly.
Yeah, I know I sound Scrooge-y. Now get back to work, dang it! You ain't gettin' a day off this year.

It's interesting to see everyone's thoughts on this. I'm glad to know I'm not the only one who had an idea of this sort. It's interesting the episode hinted so much that the darkness was a symbiote/being of some kind but never outright stated it.
I think Grogar might have been deconfirmed from ever appearing in the main series. In "A Flurry of Emotions," the storybook Spike read to the kids featured a villain named Grogar. I think that might have been the show staff's way of using Grogar's name without actually making him a character.

Sadly, this is apparently the nature of debates in general on the Internet.
Actually, I guess it's real life debates too.
They usually seem to devolve into attempts by both sides to gain moral highground so they can bury the opposition. Far too often, it's just glorified crap-slinging, instead of discussion on how a mutually beneficial solution can be found for the good of all concerned.

I feel like the episode was heavily hinting at this.
Stygian says that a shadow "spoke to him." This could just be general edginess, but it also suggests he merged with a sentient being, not just dark powers.
The ruin they fell into at the Hollow Shades had an image of what appeared to be a shadowy beast upon the wall. Stygian said this ruin was where he met the "shadow," which means the ruin predated the Pony of Shadows. Therefore, the building was not erected to honor the Pony of Shadows, but something else (logically, the "shadow" which resided there).
The Pony of Shadows is more snakelike than other ponies, not to mention much bigger and composed of darkness. If Stygian had simply been powered up by his dark emotions, these would be odd effects.
The Pony of Shadows apparently wants to completely obliterate all existence to return the universe to oblivion. That seems a bit blown out of proportion, even by Stygian (or Starlight's) standards.
Also, the Pony of Shadows did not disintegrate when they pulled Stygian out of it, but was instead sucked into the Limbo and sealed away. If the Pony of Shadows was just Stygian powered up by darkness, why would his pony body be capable of being separated from the snakelike body? Rather, it seems something used Stygian as a host to gain power until it was strong enough to sustain itself without Stygian (even seemingly trapping Stygian within itself).
This goes more into headcanon territory, but I also feel the Hollow Shades is likely to have been inhabited by a cult dedicated to this "shadow" god. They were the ones who built the temple, and Stygian found their cult and joined it, eventually being used as a vessel. The cult would desert the place and dismember once they realized their god had been banished by Starswirl and the others.

I heavily dislike this Firefox Quantum. It freezing to the point I have to close the window is now a regular occurrence in literally every browsing session, usually more than once. Sure, it usually restores my tabs, but it's still a massive irritation, and a few times it glitched so hard I couldn't open another Firefox window until I restarted my computer.

Funnily enough, that isn't entirely true. I believe I'm on your friends' list. However I haven't been using the site and was always a pretty quiet member so our interaction was minimal. Oh yeah, and I changed names recently as well.

I appreciate you taking the time to make this post. Your observations are very interesting to me. However I feel the need to clear up a few things on my part.
Firstly, I'm aware that my parents would still love me even if I were queer. They would disown me, yes, but I don't believe their love would truly fade, but instead be buried. I understand that when my mother said the things that she did, she was feeling very emotional; too emotional perhaps. I know that her rational side has made her regret it, because I can see her guilt in the way she acts toward me. She was motivated by love to save me from Hell, so far as she believed. And I try to appreciate that as best I can.
Secondly, it should be noted that I'm also aware both my parents have stories of their own that led them to be who they are today. They have each had quite difficult lives in a different way, which I will not recall in this post. Suffice to say, it's easy for me to see why they act how they do. And while I would be lying if I said I disagree-strongly-with their child raising methods, I can understand what they wanted to accomplish and why.
Thirdly, at the moment I am avoiding coming to any conclusions about religion or spirituality. Someone I know, trust and respect (and who is quite a bit older than me) advised me to wait several years before coming to any conclusions on religion, that I should wait to mature more before deciding anything. I greatly value that advice, and I am following it for the moment. Being a young adult is quite difficult enough without questioning the meaning of life as well, I suppose.

I doubt anyone recognizes me since I never posted in here that often (and I disappeared for awhile due to school), but I would like to reveal some of my thoughts and experiences with my religion (Christianity). The long and short of it is that I have been losing my faith in Christianity lately. I've been depressed for a long time, like "I tell myself I deserve to die at least once a week" kind of depressed. I was never able to isolate the root cause until I began to question my religion. I was hesitant to publicly share some of my past here for my parents' sake, but now I feel I have a right to share my experiences for what they are. Keep in mind as you read the following that I was raised in a fundamentalist household.
You know those stories about rich kids that are forced to live in estates and never mingle with "commonfolk?" That's pretty much the household I was raised in, only we aren't rich. Basically, the idea is "The world has been hit by a Satanic fallout kids, hide here in our bunker and you'll be safe from contamination." Ironic, considering how dysfunctional we all are... Anyway, eventually I began posting on forums behind my parents' backs. For the first time, I heard about homosexuality. I realized it was strictly prohibited by my parents' doctrine, hence why I'd never heard of it. My initial disgust turned to tentative acceptance, and I heard about the science of "It's biological". Being the rebellious little teenager I was, I started to wonder "Is that me? Am I gay?" Of course, these questions were kept hidden from my family. Then I begin to develop "feelings" for a gay guy online. I'll never know if he was a catfisher or not (probably, in hindsight there were some red flags) but younger me didn't even think about that. I went along in my happy so called "relationship", deciding that God wouldn't be against it.
Then my mother found out.
That was one hell of a morning. I had imagined if my parents ever found out, I would argue with them. I would stand up for myself. Me, the perfect little untainted trophy on my parents' shelf, would burst free and develop his own beliefs. That died quickly. There was a lot of shouting on my mother's part, and I didn't say much. I won't deny I was shaking. When I asked her if she wanted to kill me, she told me (and I quote) "Of course I want to kill you." And as she said "If your father ever founds out, he WILL kill you." I believed her too. If you saw how angry my dad gets when he rants about the world, you would too. It's humiliating to look back and see how completely cowed by her I was. Heh. Anyway, I promised to stop being gay, and she made me cut ties with my online friends. She said God would forgive me for what I did, and I believed her. Or so I thought.
Apparently my subconscious didn't, because ever since then I've been pretty consistently depressed. Granted, I was depressed to a degree before that too, but this was worse. I struggled with the idea that I deserved death for my mistakes. In the past six months or so, I've told myself weekly that I was a blight on the world that brought no good. I felt as if God were hanging over me like a weight, that I had to explain my every action to him. That limited my social capabilities; when I was allowed to talk to my friends again, my bitter mental state made me act like a complete bitch towards them, and I broke away from them. I felt that no one cared about me, not even God. Why would he? I felt scared to make decisions and to be myself. Essentially, I was hardly my own person.
Then one day I heard about conversion therapy. You can imagine my shock. As fucked up as what I had lived through was, it wasn't even close to some of the bullshit that others have lived through. That was the day I lost my faith in Christianity. I don't feel that I can stand in support of something that (to some people) justifies such horrible things. Yet according to my parents, there is only one "true Christianity" (theirs) and everyone else has interpreted it wrong. In that case, count me out of it altogether. I can't hate homosexuals or transsexuals like they do. I've tried, damn it. And I've been told that God abhores hypocrites; by definition, calling myself a Christian while supporting ones of its most taboo things would be just what He hates. Nor can I stand by a doctrine that drives me into the ground everyday, telling me that I don't deserve to live. So I am NOT a Christian anymore, and I never can be.
What I find interesting is that I feel like I've always known deep down this would happen someday. I never actually doubted my religion before. Yet even as a little boy, I felt a bit uncomfortable with my parents' cynical world view. If I were a loyal Christian, why did I often feel uneasy when God was brought up among my family? Why did I feel that, if anyone in our family failed to be a Christian, it would be me? I feel almost as if this was always who I was, and denying that was what caused my pesky depression. Because yes, my depression has subsided (for the moment, at least). And yes, I realize that as a young adult, deviating from my family is normal and it may lead to nothing. But I know this; whatever religion I choose to follow, it won't be Christianity, and it will be one that I follow because I choose to, not because my parents threatened me with eternal damnation (which they have). For the first time, I realize that I have the freedom to develop my own thoughts, my own morals, and my own path through life, not the path dictated for me.
There was actually a lot more that I wanted to say on why I'm losing faith in Christianity, but this post is already long enough as it is. Besides, I suppose this is not an entirely appropriate place for that. Even this post may offend some, which isn't my intention. You follow the religion that makes YOU happy. Hasta la vista.